A rare variant of the internal thoracic (mammary) artery

The internal thoracic (mammary) artery (ITA) is a branch of the first part of the subclavian artery. It courses downwards in the ventral thoracic wall and terminates in the musculophrenic and superior epigastric arteries. We have observed a rare variant of the right ITA in a female cadaver. The ITA terminated at the level of the second costal cartilage in 2 branches, which anastomosed with each other in a stepladder pattern. The medial branch gave sternal branches and then continued as the superior epigastric artery. The lateral branch gave anterior intercostal arteries and then continued as the musculophrenic artery. Since this artery is increasingly used as bypass graft in coronary artery bypass grafting, this variation of ITA should be borne in mind.